# find no. of electrons in(a) 3.6 grams of ammonium ion(b)3.2 grams of methane

2
by sharmakshitij

2014-05-12T13:56:32+05:30
This is an easy one, but requires thinking :P
a) No. of electrons in 3.6 gm of ammonium ion.

Ans. Ammonium Ion is (NH4)
This means that Ammonium Ion is formed by losing one electron.
No. of Protons is equal to Atomic number of N + 4 times atomic number of Hydrogen.
=> No. of protons in NH4 is 7 + 4 = 11
SInce NH4 is positively charged, there should be 10 electrons [so that it is plus 1 positively charged]
=> 1 atom of NH4 contains 10 electrons.
SInce 1 mole contains NA [Avogadro's number] number of ions of NH4,
1 mole of NH4 will contain NA*10 electrons.
3.6 gm of Ammonium ion is 3.6/18 moles of NH4 = 1/5 moles = 0.2 moles of NH4.
1 mole of NH4 contains NA*10 e-.
=> 0.2 moles of NH4 contains NA*10*0.2 e-
= 2NA electrons =

b) I hope you are a true science student, and can find the same for 3.2 gm of Methane, that will be
The above is the no. of electrons of 3.2 gm of CH4.
I think we have got same answers, isn't it ? :-)

2014-05-12T14:09:48+05:30
(a)3.6 gms of NH4+ means 3.6/18 moles=0.2 moles
no. of electrons in 3.6 gms of NH4+=0.2*6.023*10^23*10
(There are 10 electrons and 11 protons in NH4+).              [no. of moles=given wt./G.M.W.]
=12.046*10^23 e-
(b)3.2 gms of CH4 means 3.2/16 moles=0.2 moles
no. of electrons in 3.2 gms CH4=0.2*6.023*10^23*10
(there are 10 electrons and 10 protons in CH4)
=12.046*10^23 e-
actually u multipled no. of moles to avagadro no.
it shouldn't be so,in this way we get no. atoms/molecules but not electrons
:o